In the field of lighting technology, light emitting diodes, referred to with the abbreviation LED, are frequently used as a light source instead of the conventional halogen bulbs. Among the lights of motor vehicles light guides occupy a special position as their elongated shape makes them especially suitable to create light lines positioned along the outline of headlights, or separately to create warning lights, e.g. positional, brake, indicator, or daily orientation lights. At present, light guides often fulfill signal light functions subject to higher requirements for the luminous flux, e.g. the day-time running lamps in headlights and the rear brake and direction indication lights in the rear lamps. Sometimes they are used where a bright, uniform appearance for the side repeater, which is incorporated into the side mirror, is requested.
The document U.S. Pat. No. 7,699,511 describes a turn lamp with a base housing; a light source unit incorporated with a light source, e.g. LED, and housed in the base housing; an inner housing has a long and solid light guide; and a lens cover covers the base housing. A diffused reflection generator is structured such that light from the light source leaks out from the light guide. The light source is arranged at a longitudinal end portion of the light guide. The base housing has a body portion that is integrally molded from a non-translucent resin material. A disadvantage of this design is that it requires a relatively thick packaging space to accommodate the lens cover and several light sources to achieve a uniform appearance.
The document EP1657111 discloses a lamp with an optical fiber, including a set of deflecting structures, which deflects light that falls on the structures in such a manner that the light comes out of a front side of the optical fiber. A set of optically operative structures is arranged over a length of the optical fiber and a part of the remaining light is emitted in angular areas extending transverse to a driving direction.
A disadvantage of this design is that it still requires a secondary lens to act as an outer lens to protect the light guide. This increases the required packaging space and requires an additional molded part for the exterior lens.
The document US20090284365 discloses a light module having visible-light emitting light source, e.g. LED, coupled to one of a set of light guiding elements and an infrared light emitting light source coupled to one of the light guiding elements. A major portion of a longitudinal extension between ends and opposite ends, respectively of the light guiding elements, follows an outer contour. The light guiding elements emit light along the major portion of the longitudinal extensions. The light sources are coupled to the light guiding elements.
As shown in FIG. 2b, this design does not include any method to protect the optical elements from the environment and will require an additional outer lens to protect the optical surfaces. Additionally, this design does not address a method for extracting light from the guides.
The technical solutions mentioned above all require an exterior lens to protect the optical system, generally a light guide. This requires significant packaging space for the lamp, which is not available in certain applications. Many lamps, particularly; side repeaters, side mounter turn signals, and applique lamps; have very narrow packaging space requirements, which makes it difficult and in some cases not possible to fit a light guide and an outer lens with an air gap between. In the prior designs, a number of optical systems are known where an indirect reflector is used behind either a grained/textured or volumetric-diffusing lens with a narrow area in between individual reflector segments. Alternatively, a light guide may be used in place of an indirect reflector. For a truly homogeneous appearance, two diffuser lenses are needed. One of the diffusers may also be the outer lens. This type of design is also undesirable for the applications mentioned because it requires too much package space because space is required for multiple lenses as well as clearance spaces to account for variations in assembly and molding.
Therefore, it is very desirable to provide a light device that overcomes the shortcomings and disadvantages of the previous light designs noted above.